Catalyst combustion device

ABSTRACT

A catalytic combustion apparatus comprises a combustor  11 , a fuel tank  12 , a valve  13 , and an ignition device  14 . The combustor  11  further comprises a gas nozzle  16 , an air intake/ejector  17 , a mixing chamber  18 , a firing chamber  19 , an ignition plug  20 , a combustion chamber  21 , a catalyst for combustion  22  housed inside the combustion chamber  21 , and an exhaust port  23 . The mixing chamber  18  is made into a straight cylindrical passage, a cylindrical firing chamber  19  is provided in parallel to the mixing chamber  18  so that an opening  24  on the side of the firing chamber  19  communicates with the combustion chamber  21 , a burner port  25  is disposed on the boundary between the mixing chamber  18  and the firing chamber  19 , and the burner  25  is configured with a catalytic net  25   a . With this configuration, a flame is formed on the upstream side of the catalyst for combustion  22 , the catalyst for combustion  22  is heated by the heat of the flame to a catalytic combustion enabling temperature thus also effecting catalytic combustion on the catalytic net  25   a . The flame spontaneously disappears, and the catalyst for combustion  22  commences catalytic combustion. As catalytic combustion can be effected without fail even when the combustion chamber  21  is configured into a low profile, the thickness of the catalytic body can be reduced without reducing the combustion characteristics, thereby enabling reduction in the height of the burner and providing a downsized and thin catalytic combustion apparatus.

FIELD OF THE INVENTION

The present invention relates to a catalytic combustion apparatus forcombustion of gaseous fuel or liquid fuel.

BACKGROUND OF THE INVENTION

An existing catalytic combustion apparatus is of a configuration asillustrated in FIG. 29, for example. In the diagram, numeral 1 is a gastank for storing liquefied petroleum gas such as butane, propane, andthe like. Fuel gas contained inside the gas tank 1 is ejected from a gasnozzle 3 passing through a gas passage 2. The gas ejected from the gasnozzle 3 draws in air through an air intake 4 by the effect of gas flowejection and is mixed with air in a mixing chamber 5, and is thensupplied to a combustion chamber 6. There being a catalytic body 7inside the combustion chamber 6, the mixed gas burns by the catalyticaction as it passes an internal passage 7′ of the catalytic body 7 andgenerates combustion heat. An ignition device 8 is provided opposite themixed gas entrance of the combustion chamber 6. When starting theapparatus, the mixed gas is ignited by a spark generated by a spark plug9 provided on the tip of the ignition device 8. The catalytic body 7 isheated by a flame formed downstream of the catalytic body 7. When thetemperature of the catalytic body 7 reaches the active temperature,catalytic combustion starts to take place on the surface of thecatalytic body 7, the supply of the mixed gas to the flame is stopped,and the flame disappears. Under this condition, the mixed gas suppliedto the combustion chamber 6 undergoes catalytic combustion over theentire catalytic body 7, and the combustion gas is exhausted from anexhaust port 10.

Such a catalytic combustion apparatus is being used in portable ironsand warming devices.

However, as such existing catalytic combustion apparatus suffers severalproblems when trying to make it smaller and thinner for betterportability, there was a limit in the improvement of portability.

To be more specific, an existing catalytic body 7 is generally acylindrical honeycomb made of ceramic or metal supporting a catalyst. Asits diameter is roughly determined by the amount of combustion, theheight of the burner cannot be made smaller than this diameter.Furthermore, when the catalytic body 7 is made unreasonably small, itwill present a problem of not being able to obtain a predeterminedheating value as the combustion characteristic is lowered.

Additionally, as existing catalytic combustion apparatuses areconfigured in a straight line by directly coupling a mixing chamber 5and a catalytic body 7, the total length of the burner tends to belarge. Though the combustion chamber 5 may be bent in order to make thelength shorter, such configuration will suffer non-uniform distributionof the mixed gas flow velocity and will result in non-uniform combustionon the catalytic body 7, thereby presenting fundamental difficulty inmaking the size smaller. Also, when the catalytic body 7 is formed intothe shape of a thin plate, the velocity of flow of the mixed gas becomeshigh when a flame for the purpose of firing is formed on the downstreamside of the catalytic body 7, and the flame is formed apart from thecatalytic body 7, thereby either delaying or stopping transition tocatalytic combustion. Downsizing will also suffer a problem of causing ahigher watt density, leading to an excessive increase in the catalysttemperature thereby shortening the life of the catalyst.

The present inventors had already developed a thin type catalyticcombustion system in which the height of the burner was made low bydisposing a catalytic body formed in the shape of a flat plate with itsplanar area greater than the area of the side, and providing a gaspassage on the catalytic body to allow flow of mixed gas in the lateraldirection. However, in manufacturing a low-profile burner, difficultieswere faced in the method of fabrication. To be more specific, whenemploying a structure in which a nozzle, a catalytic body, etc., aremounted onto a mother component in which a mixing chamber, a combustionchamber, etc., have been formed into a single piece by aluminum diecasting, for example, there was a limit in making the mother componentthinner in which the mixing chamber and the combustion chamber had beenintegrally formed into a single piece from the standpoint of thethickness of molding, etc., to say nothing of the difficulty in securingprecision.

SUMMARY OF THE INVENTION

The present invention addresses the above described issues of the priorart. It is an object of the present invention to make a smaller andthinner burner by making the height and length smaller while securingignitability thereby to provide a catalytic combustion apparatus whichis superior in durability and portability.

A description will now be given of exemplary embodiments of the presentinvention for achieving the above objective.

A first exemplary embodiment of the present invention comprises acombustor, a fuel tank, a valve, and an ignition device, wherein thecombustor further comprises a gas nozzle, an air intake/ejector, amixing chamber, a firing chamber, an ignition plug, a combustionchamber, a catalyst for combustion (first catalyst) housed in thecombustion chamber, and an exhaust port. The mixing chamber is astraight cylindrical passage, a cylindrical firing chamber of which anopening on its side communicating with the combustion chamber isprovided in parallel to the mixing chamber, a burner port is disposed onthe boundary of the mixing chamber and the firing chamber, and theburner port comprises a catalytic net (second catalyst). With thisstructure, it is made possible to form a flame on the upstream side ofthe catalyst for combustion, and heat the catalyst for combustion to acatalytic combustion enabling temperature with the heat of the flamethus causing catalytic combustion on the catalytic net, too, whereby theflame spontaneously disappears allowing the catalyst for combustion tocommence catalytic combustion, and suggesting that catalytic combustioncan be performed without fail even when the combustion chamber isconfigured with a low profile. Furthermore, as the combustion takesplace on both the catalytic net and the catalyst for combustion, thetemperature rise of the catalyst for combustion is kept small and thelife is lengthened. As a result, the thickness of the catalytic body canbe made smaller without sacrificing the igniting characteristics anddurability, thereby allowing the burner height to be made smaller andproviding a smaller and thinner catalytic combustion apparatus.

A second exemplary embodiment is configured such that, in a catalyticcombustion apparatus as described in the first exemplary embodiment, thecombustion on the catalytic net, is adjusted to half of the entirecombustion thereby to quickly extinguish the flame to allow smoothtransition to catalytic combustion as well as to halve the combustion onthe catalytic net thus lengthening the life of both the catalytic netand the catalyst for combustion.

A third exemplary embodiment of the present invention comprises acombustor, a fuel tank, a valve, and an ignition device, wherein thecombustor further comprises a gas nozzle, an air intake/ejector, an airintake, a mixing chamber, a firing chamber, a burner port provided inthe firing chamber, an ignition plug, a combustion chamber, a catalystfor combustion housed in the combustion chamber, and an exhaust port. Anintake-air shutter is provided on the air intake which is operable by atemperature detecting means provided in the vicinity of the combustionchamber. With this arrangement, the ratio of combustion on the catalyticnet can be lowered by making the velocity of the fuel air mixed gaspassing through the catalytic net greater by increasing the air-to-fuelratio after transition to catalytic combustion, thereby to secure thelife of the catalytic net. Also, by increasing the air-to-fuel ratio,the temperature of the catalyst for combustion is lowered and thedurability is improved.

A fourth exemplary embodiment is a catalytic combustion apparatus asdescribed in the first exemplary embodiment comprising a combustor, afuel tank, a valve, and an ignition device, wherein the combustorfurther comprises a gas nozzle, an air intake/ejector, an air intake, amixing chamber, a firing chamber, a burner port provided in the firingchamber, an ignition plug, a combustion chamber, a catalyst forcombustion housed in the combustion chamber, and an exhaust port. Aquantity-of-flow adjustable means is provided between the valve and thecombustor so that the adjustable range of the amount of combustion canbe widened in a manner such that when the quantity of gas flow isreduced by adjusting the quantity-of-flow adjustable means, combustionwill take place on the combustion net only, and when the quantity of gasflow is increased, combustion will take place on both the catalytic netand the catalyst for combustion.

A fifth exemplary embodiment is an invention as described in the firstexemplary embodiment comprising a combustor, a fuel tank, a valve, andan ignition device, in which the combustor further comprises a gasnozzle, an air intake/ejector, an air intake, a mixing chamber, a firingchamber, an ignition plug, a combustion chamber, a catalyst forcombustion housed in the combustion chamber, and an exhaust port. Themixing chamber is a straight cylindrical passage, a cylindrical firingchamber a side opening of which communicating with the combustionchamber is provided in parallel to the mixing chamber, a burner port isprovided on the boundary between the mixing chamber and the firingchamber, the burner port is configured with a catalytic net, and themixing chamber and a part of the catalytic net are made to come intocontact with each other so that the heat of the catalytic net can beconducted to the combustor through the wall of the mixing chamber,thereby suppressing the temperature rise of the catalytic net andsecuring the life of the catalytic net.

A sixth exemplary embodiment is one in which the catalytic net of thefifth exemplary embodiment is formed in the shape of a square letter Cso that its two sides come into contact with the wall of the mixingchamber thereby to remove dispersion of the area of contact between themixing chamber and the catalytic net during assembly work and to obtainstable characteristics.

A seventh exemplary embodiment is a catalytic combustion apparatus asdescribed in the fifth exemplary embodiment, in which the catalytic netis formed in the shape of an open square so that its three sides comeinto contact with the wall of the mixing chamber. As it is made easy tomaintain the shape of the catalytic net, dispersion of the area ofcontact between the mixing chamber and the catalytic net during assemblywork can be removed, and stable characteristics can be obtained.

An eighth exemplary embodiment is a catalytic combustion apparatus, inwhich the ignition plug is disposed in the end of the firing chamberwhere the density of combustion gas becomes high thereby to assurefiring and allow reduction in size and thickness.

A ninth exemplary embodiment is a catalytic combustion apparatus, inwhich a part of the catalyst for combustion is disposed in such a waythat it projects into the firing chamber thereby to increase the speedof transition to catalytic combustion by increasing the rate oftemperature rise of the catalyst for combustion and allow reduction insize and thickness.

A tenth exemplary embodiment is a catalytic combustion apparatus, inwhich the air intake/ejector is provided with a quantity-of-flowadjustable means for varying the quantity of intake air thereby toimprove combustion characteristics during catalytic combustion byincreasing the ratio of excess air upon transition to catalyticcombustion and allow reduction in size and thickness.

An eleventh exemplary embodiment is a catalytic combustion apparatus, inwhich the valve comprises a solenoid valve and a control apparatus, andthe control apparatus controls the solenoid valve in a manner such thatthe control apparatus temporarily closes the solenoid valve after anignition device has operated and subsequently opens it again thereby toassure smooth transition to catalytic combustion and allow reduction insize and thickness.

A twelfth exemplary embodiment is a catalytic combustion apparatus, inwhich the valve is provided with a quantity-of-flow adjustable means foradjusting the quantity of intake air, and the quantity-of-flowadjustable means is fully opened to allow the ignition device to ignite,and throttles back the quantity of supply of fuel gas after ignitionthereby to assure stable ignition and transition to catalytic combustionand to allow reduction in size and thickness.

A thirteenth exemplary embodiment is a catalytic combustion apparatus,in which the valve comprises a solenoid valve and a control apparatus,and the control apparatus controls the solenoid valve to be temporarilyclosed based on a signal from a temperature detecting means disposed inthe combustion chamber thereby to assure ignition and stable transitionto catalytic combustion and to allow reduction in size and thickness.

A fourteenth exemplary embodiment is a catalytic combustion apparatus,in which the exhaust port is disposed on the combustor in such a mannerthat it will not overlap the combustion chamber and will come to aposition opposite the direction of ejection of mixed gas into the mixingchamber thereby to allow uniform catalytic combustion through uniformpassage of the mixed gas through the catalyst for combustion andreduction in size and thickness.

A fifteenth exemplary embodiment is a catalytic combustion apparatus, inwhich a burner port area adjustable means provided on the combustor isoperable with a signal from a temperature detecting means provided inthe vicinity of the burner port thereby to allow instantaneoustransition to catalytic combustion by reducing the open area of theburner port upon reaching a catalytic combustion enabling temperature.

A sixteenth exemplary embodiment is a catalytic combustion apparatus, inwhich the catalyst for combustion is affixed to the combustion chamberwith a space between itself and the inner wall of the combustion chamberthereby to reduce the quantity of transfer of the heat generated by thecatalyst for combustion to the combustor and to keep the temperature ofthe outer wall low even when the apparatus is downsized to obtainuser-friendliness.

A seventeenth exemplary embodiment is a catalytic combustion apparatus,in which the catalyst for combustion is provided with a thicknessadjustable means for adjusting thickness thereby enabling adjustment ofthe quantity of heat transfer to the combustor in order to obtain a widetemperature control range.

An eighteenth exemplary embodiment is a catalytic combustion apparatus,in which a catalytic body formed into the shape of a flat plate of whichthe area of the planar surface is greater than the area of the side isdisposed inside the combustion chamber and a gas passage to allow flowof mixed gas in the lateral direction is provided on the catalytic body,thereby making the burner height low and providing a small sized andthin catalytic combustion apparatus.

A nineteenth exemplary embodiment is a catalytic combustion apparatus,in which a straight cylindrical gas passage communicating with theoutlet of the mixing chamber is provided and the inlet of the combustionchamber is made to communicate with a side of the gas passage so thatthe mixing chamber and the catalytic body are disposed in parallel toeach other thereby to shorten the burner length to obtain a compactdesign.

A twentieth exemplary embodiment is a catalytic combustion apparatus, inwhich the length of the straight cylindrical gas passage is made longerthan the width of the inlet of the combustion chamber and the inlet ofthe combustion chamber is disposed inside the straight cylindrical gaspassage thereby to allow more uniform mixing of fuel gas and air and touniformly supply the mixed gas to the catalytic body.

A twenty-first exemplary embodiment is a catalytic combustion apparatus,in which a gas flow resistant body is provided in the outlet of themixing chamber to reduce the velocity of mixed gas flow thereby to slowdown the velocity of the mixed gas flow inside the straight cylindricalgas passage and to uniformly supply the mixed gas to the catalytic body.

A twenty-second exemplary embodiment is a catalytic combustionapparatus, in which a gas rectifier is provided in the inlet of thecombustion chamber to rectify the flow of mixed gas thereby to rectifythe mixed gas that comes out from the straight cylindrical gas passageand to uniformly supply the mixed gas to the catalytic body.

A twenty-third exemplary embodiment is a catalytic combustion apparatus,in which the catalytic body supports a catalyst on a corrugated carriermade by folding a thin metal sheet into the shape of continuous wavesthereby to provide a catalytic body which is simple in shape, simple tocontinuously. process, and superior in mass producibility.

A twenty-fourth exemplary embodiment is a catalytic combustionapparatus, in which the catalytic body supports a catalyst on amultilayer carrier fabricated by alternately stacking a corrugated sheetmade by folding a thin metal sheet into the shape of continuous wavesand a flat thin metal sheet thereby to secure high combustion efficiencyeven when the amount of combustion is increased.

A twenty-fifth exemplary embodiment is a catalytic combustion apparatuscomprising a nozzle for ejecting a fuel gas, a mixing chamber for makinga mixed gas by mixing the fuel gas ejected from the nozzle and air, anda combustion chamber having a catalytic body inside it for burning themixed gas, in which the combustion chamber is comprised of discretecomponents which can be divided into the mixing chamber, nozzle, andcatalytic body, thereby to provide a small and thin catalytic combustionapparatus with a low burner height.

A twenty-sixth exemplary embodiment is a catalytic combustion apparatus,in which the combustion chamber comprises a plurality of componentsdivided by a plane approximately in parallel with the direction ofejection from the nozzle thereby to lower the height of the combustionchamber.

A twenty-seventh exemplary embodiment is a catalytic combustionapparatus, in which a subassembly integrating the combustion chamber andthe nozzle is secured by sandwiching a plurality of components thatcomprise the combustion chamber thereby to downsize the mixing chamberand the nozzle.

A twenty-eighth exemplary embodiment is a catalytic combustionapparatus, in which a temperature detecting means for detecting thetemperature of the combustion chamber and a control unit for controllingthe quantity of ejection of the fuel gas based on the output of thetemperature detecting means are provided. The temperature detectingmeans is secured by a plurality of components that comprise thecombustion chamber thereby to simplify the structure of affixing thetemperature detecting means to the combustion chamber, downsize thecombustion chamber, as well as to assure securing of the temperaturedetecting means by sandwiching it with the combustion chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of the overall structure of a catalyticcombustion apparatus in a first example of the present invention.

FIG. 2 is a cross-sectional view of the overall structure of a catalyticcombustion apparatus in the first example of the present invention.

FIG. 3 is a cross-sectional view of the overall structure of a catalyticcombustion apparatus in the first example of the present invention.

FIG. 4 is a cross sectional view of the structure of a combustor of acatalytic combustion apparatus in the first example of the presentinvention.

FIG. 5 is a cross-sectional view of an essential part of the combustorof a catalytic combustion apparatus in the first example of the presentinvention.

FIG. 6 is a cross-sectional view of an essential part of the combustorof a catalytic combustion apparatus in the first example of the presentinvention.

FIG. 7 is a cross-sectional view of an essential part of the combustorin the first example of the present invention.

FIG. 8 is a cross-sectional view the structure of the combustor in thefirst example of the present invention.

FIG. 9 is a cross-sectional view of the structure of a catalyticcombustion apparatus in the first example of the present invention.

FIG. 10 is a cross-sectional view of an essential part of a catalyticcombustion apparatus in a second example of the present invention.

FIG. 11 is a cross-sectional view of an essential part of a catalyticcombustion apparatus in a third example of the present invention.

FIG. 12 is a cross-sectional view of the overall structure of acatalytic combustion apparatus in a fourth example of the presentinvention.

FIG. 13 is a cross-sectional view of the overall structure of acatalytic combustion apparatus in a fifth example of the presentinvention.

FIG. 14 is a cross-sectional view of the overall structure of acatalytic combustion apparatus in a sixth example of the presentinvention.

FIG. 15 is a cross-sectional view of the structure of a combustor of acatalytic combustion apparatus in a seventh example of the presentinvention.

FIG. 16 is a cross-sectional view of the structure of a combustor of acatalytic combustion apparatus in an eighth example of the presentinvention.

FIG. 17 is a cross-sectional view of a state in which a burner port areaadjustable means is in operation in the eighth example of the presentinvention.

FIG. 18 is a cross-sectional view of the structure of a combustionchamber of a catalytic combustion apparatus in a ninth example of thepresent invention.

FIG. 19 is a cross-sectional view of the structure of a combustionchamber of a catalytic combustion apparatus in a tenth example of thepresent invention.

FIG. 20 is a cross-sectional view of a state in which a thicknessadjustable means is in operation in a catalytic combustion apparatus inthe tenth example of the present invention.

FIG. 21 is a cross-sectional view of the structure of a catalyticcombustion apparatus in an eleventh example of the present invention.

FIG. 22 is a perspective view to illustrate the structure of a catalyticbody employed in a catalytic combustion apparatus in the eleventhexample of the present invention.

FIG. 23 is a cross-sectional view of the section housing the catalyticbody in the catalytic combustion apparatus in the eleventh example ofthe present invention.

FIG. 24(a) is a disassembled perspective view of a catalytic bodyemployed in a catalytic combustion apparatus in a twelfth example of thepresent invention, and FIG. 24(b) is a perspective view of the catalyticbody after being assembled.

FIG. 25 is a perspective view to illustrate the structure of a catalyticbody employed in a catalytic combustion apparatus in a thirteenthexample of the present invention.

FIG. 26 is a cross-sectional view to illustrate the structure of acatalytic combustion apparatus in a fourteenth example of the presentinvention.

FIG. 27 is a disassembled side view of a catalytic combustion apparatusin the fourteenth example of the present invention.

FIG. 28 is a top view of the catalytic combustion apparatus in thefourteenth example of the present invention.

FIG. 29 is a cross-sectional view to illustrate the structure of a priorart catalytic combustion apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description of exemplary embodiments of the present invention will begiven in the following.

EXAMPLE—1

FIG. 1 is a cross-sectional view to illustrate the overall structure ofa catalytic combustion apparatus. Numeral 11 is a combustor, numeral 12is a fuel tank, numeral 13 is a valve, numeral 14 is an ignition deviceusing a piezoelectric element, numeral 16 is a gas nozzle, numeral 17 isan ejector for drawing in air by the ejecting energy of fuel, numeral 18is a straight cylindrical mixing chamber for mixing a fuel gas and air,and numeral 19 is a cylindrical firing chamber of which an opening 24 onthe side communicates with a combustion chamber 21. Numeral 20 is anignition plug for generating a spark inside the firing chamber 19,numeral 22 is a catalyst for combustion housed inside the combustionchamber 21, numeral 23 is an exhaust port for discharging combustiongas. Numeral 25 is a burner port provided on the boundary between themixing chamber 18 and the firing chamber 19 and is configured with acatalytic net 25 a which supports a catalyst with platinum as the maincomponent on a high heat resistance metal net. The catalytic net 25 asupports approximately 2.5 mg of platinum which is capable of burning 70to 80% of the fuel gas. A flame is formed on the catalytic net 25 a,whereby the catalyst for combustion 22 is heated to catalytic combustionenabling temperature. A flame is formed on the burner port 25 by openingthe valve 13 to allow ejection of the fuel gas from the gas nozzle 16and igniting it with the ignition device 14. As the burner is made thin,the area of the opening of the burner port 25 is made small and thevelocity of flow of the mixed gas is made high thereby forming a flameat some distance from the burner port 25. As a result, the flameapproaches the catalyst for combustion 22, the catalyst for combustion22 is easily heated, and the temperature of the catalyst for combustion22 reaches 200 degrees C. or higher in several seconds which isgenerally regarded as the catalytic combustion enabling temperature. Asthe heat capacity of the catalytic net 25 a is small, its temperatureinstantly rises even when a flame is formed apart from it, and catalyticcombustion commences on the catalytic net 25 a almost simultaneously.The flame formed on the burner port spontaneously disappears, andcatalytic combustion commences on the catalyst for combustion 22. Ascatalytic combustion can be securely effected in this way even when thecombustion chamber 21 is configured thin, the thickness of the catalystfor combustion 22 can be reduced without lowering the firingcharacteristic. Furthermore, as combustion takes place on both thecatalytic net 25 a and the catalyst for combustion 22, the temperatureof the catalyst for combustion 22 remains low thus lengthening its life.Consequently, the burner height can be reduced while securing the firingperformance and durability thereby enabling downsizing and thin design.

In the catalytic combustion apparatus of FIG. 1, by making the quantityof platinum supported by the catalytic net 25 a to be approximately 1.7mg and adjusting the combustion on the catalytic net 25 a to beapproximately half, namely, 40 to 70%, of the entire combustion, a flamecan be quickly put out while undergoing smooth transition to catalyticcombustion, and at the same time the combustion on the catalytic net 25a can be halved thereby lengthening the life of both the catalytic net25 a and the catalyst for combustion 22.

FIG. 2 and FIG. 3 are cross-sectional views to illustrate the overallstructure of a catalytic combustion apparatus. Numeral 26 is an airintake. Numeral 27 is an air-intake shutter comprising an L-shapedshutter 27 a, an aperture for air intake 27 b, and a tension spring 27c. The size of the aperture for air intake is designed to a size atwhich the quantity of air necessary for forming a flame at the burnerport without fail can be taken in. Numeral 28 is a temperature detectingmeans provided in the vicinity of the combustion chamber 21 andcomprises a case 28 a, a bimetal 28 b, and an operating rod 28 c. Theremaining configuration is the same as in FIG. 1. The operatingtemperature of the temperature detecting means 28 is set atapproximately 250 degrees C. which is slightly higher than the catalyticcombustion enabling temperature. The catalyst for combustion 22 isheated by a flame formed at the burner port 25, and the temperature ofthe catalyst for combustion 22 rises in several seconds to 200 degreesC. or higher which is generally regarded as a catalytic combustionenabling temperature. As the heat capacity of the catalytic net 25 a issmall, its temperature instantly rises and catalytic combustioncommences almost simultaneously on the catalytic net 25 a, the flameformed on the burner port spontaneously disappears, and catalyticcombustion commences on the catalyst for combustion 22. When thetemperature of the catalyst for combustion 22 rises to 250 degrees C.which is higher than the catalytic combustion enabling temperature, thetemperature detecting means 28 operates to open the air-intake shutter27, the area of the aperture is increased, and the quantity of theintake air is increased. By making the air-to-fuel ratio higher aftertransition to catalytic combustion, the ratio of combustion on thecatalytic net 25 a is reduced by making the velocity of flow of mixedgas of the fuel gas and air faster, thereby lengthening the life of thecatalytic net 25 a. Furthermore, by increasing the air-to-fuel ratio,the temperature of the catalyst for combustion is also reduced thusenhancing durability.

FIG. 4 is a cross-sectional view to illustrate a combustor of thecatalytic combustion apparatus. Numeral 29 is a quantity-of-flowadjustable means such as a needle valve provided between a valve 13 anda combustor 11. The remaining structure is the same as the catalyticcombustion apparatus in FIG. 1. When the quantity of flow of the fuelgas is reduced by controlling the quantity-of-flow adjustable means 29,as the generated heat is insufficient, catalytic combustion cannot bemaintained on such a catalyst with a large heat capacity as the catalystfor combustion 22. However, as the heat capacity of the catalytic net 25a is small, catalytic combustion can be maintained even with a smallamount of heat generation. Consequently, the adjustable range of theamount of combustion is widened by burning on the catalytic net 25 aonly when the flow rate is low, and burning on both the catalytic net 25a and the catalyst for combustion 22 when the flow rate of the fuel gasis increased.

FIG. 5 is a cross-sectional view of an essential part of the combustionchamber of the catalytic combustion apparatus. Here, a mixing chamber 18and a part of a catalytic net 25 a are in contact with each otherthereby to transfer heat of the catalytic net 25 a to the combustor 11through the wall of the mixing chamber 18, control the temperature riseof the catalytic net 25 a, and lengthen the life of the catalytic net 25a.

FIG. 6 is a cross-sectional view of an essential part of a combustionchamber of another example of a catalytic combustion apparatus. Numeral11 is a straight cylindrical passage having a rectangular cross-sectionand numeral 25 a is a catalytic net formed to the shape of a squareletter C. Here, the above described catalytic net 25 a is formed to theshape of a square letter C so that it comes into contact with the mixingchamber 18 on two sides. This way, the dispersion of the area of contactbetween the mixing chamber 18 and the catalytic net 25 a during assemblywork can be eliminated and stable characteristics can be obtained.

FIG. 7 is a cross-sectional view of an essential part of a combustionchamber of still another example of a catalytic combustion apparatus.Numeral 11 is a straight cylindrical passage having a rectangular crosssection and numeral 25 a is a catalytic net formed to the shape of asquare. Here, the catalytic net 25 a is formed to the shape of a squareso that it comes into contact with the mixing chamber 18 on three sides.This way, by making it easy to maintain the shape of the catalytic net25 a, the dispersion of the area of contact between the mixing chamber18 and the catalytic net 25 a during assembly work can be eliminated andfurther stabilized characteristic can be obtained.

FIG. 9 is a cross-sectional view to illustrate the structure of a partof the catalytic combustion apparatus shown in FIG. 1 to FIG. 4. Acatalytic net 25 a is housed inside a mixing chamber 18. In other words,the catalytic net 25 a is disposed on the upper part of the burner port25 described in the first example. As the heat capacity of the catalyticnet 25 a is small and the temperature rises to a predeterminedtemperature in a short period of time, it has extremely highflame-keeping effect. Consequently, a flame once formed by ignition of amixed gas will not disappear due to the flame-keeping effect of theabove-mentioned catalytic net 25 a.

As a result, according to this example, a flame can be formed on thecatalytic net 25 a without fail, transition to catalytic combustion canbe effected without fail even when the combustion chamber 21 isconfigured thin, thereby realizing a downsized and thin catalyticcombustion apparatus.

EXAMPLE—2

Next, a description will be given of a second example. FIG. 10 is across-sectional view of an essential part of a catalytic combustionapparatus of this example. In this example, a portion 22 a of a catalystfor combustion 22 is disposed in a manner such that it projects into afiring chamber 19.

In the first example, as illustrated in FIG. 8, the catalyst forcombustion 22 is housed inside the combustion chamber 21. As thecombustion chamber 21 is of dense structure, the heat capacity is largeand it takes time for the catalyst for combustion 22 to reach apredetermined temperature. In contrast to this, in the presentembodiment, the portion 22 a of the catalyst for combustion 22 isdisposed in a manner such that it projects into the firing chamber 19 asdescribed above. Most of the firing chamber 19 is an empty space with anextremely small heat capacity compared with that of the combustionchamber 21. Accordingly, in this example, the time during which thecatalyst for combustion 22 reaches a predetermined temperature is madeshorter by disposing a portion 22 a of the catalyst for combustion 22inside the firing chamber 19 with a small heat capacity.

As has been described above, according to this example, the speed oftransition to catalytic combustion can be made faster by making the rateof temperature rise of the catalyst for combustion 22 higher therebyrealizing a downsized and thin catalytic combustion apparatus.

EXAMPLE—3

Next, a description of a third example of the present invention will begiven. FIG. 11 is a cross-sectional view of a combustor 11 of acatalytic combustion apparatus in this example. In this example, aquantity-of-flow adjustable means 29 is provided on an air intake 30.The quantity-of-flow. adjustable means comprises an opening/closing lid29 a and an opening/closing spring 29 b. On the opening/closing lid 29a, an opening 29 c which is smaller than the open area of the air intake30 is provided. The size of the opening 29 c is designed in a mannersuch that an optimum quantity of air for ignition can be taken in.

In other words, when a user depresses the quantity-of-flow adjustablemeans 29 with a finger, the opening/closing lid 29 a overcomes thepressure of the opening/closing spring 29 b and covers the surface ofthe air intake 30. As a result, the air to be taken in by an airintake/ejector 17 goes through the opening 29 c which is provided on theopening/closing lid 29 a. In this way, when igniting, the airintake/ejector 17 takes in a small quantity of air thereby to supply amixed gas with a low excess air ratio to a mixing chamber 18. The mixedgas with low excess air is easily fired meaning that firing can be donewithout fail. When the user releases the finger from thequantity-of-intake-air adjustable means 29 after firing has been done inthis way, the opening/closing lid 29 a is detached from the surface ofthe air intake 30 by the pushing force of the opening/closing spring 29b. That is, the air to be taken in by the air intake/ejector 17 duringcatalytic combustion goes through the air intake 30. Consequently,during catalytic combustion, the air intake/ejector 17 supplies to themixing chamber 18 a mixed gas with a high excess air ratio by taking ina large amount of air.

As has been described above, in the third example, the amount of air inthe mixed gas can be set at an optimum excess air ratio for each offiring and catalytic combustion thereby providing a downsized and thincatalytic combustion apparatus having a superior combustioncharacteristic of catalytic combustion.

EXAMPLE—4

A description of a fourth example of the present invention will now begiven. FIG. 12 is a cross-sectional view to illustrate the overallstructure of a catalytic combustion apparatus of this example. In thisexample, the valve as described in each of the above-described examplescomprises a solenoid valve 34 and a control apparatus 35. The controlapparatus 35 further comprises a timer circuit 36 and a relay circuit37.

To be more specific, in this example, the apparatus is controlled in amanner such that the solenoid valve 34 is temporarily closed by thetimer circuit 36 and the relay circuit 37 for a certain period of timeafter an ignition device 14 has operated, and is reopened after apredetermined period of time has elapsed. Adoption of the aboveconfiguration enables extinction of a flame without fail after acatalyst for combustion 22 has been heated and stable transition tocatalytic combustion occurs.

As has been described above, according to the fourth example, stabletransition to catalytic combustion is enabled and a downsized and thincatalytic combustion apparatus is realized.

EXAMPLE—5

Next, a description will be given of a fifth example of the presentinvention. FIG. 13 is a cross-sectional view to illustrate the overallstructure of a catalytic combustion apparatus of this example. In thisexample, a quantity-of-flow adjustable means 38 is provided on a valve13. The quantity-of-flow adjustable means 38 has a cock 38 a. In thisexample, by manually opening and closing the cock 38 a, the quantity offuel gas to be supplied from a fuel tank 12 can be adjusted.

To be more specific, the cock 38 a is fully opened when igniting so asto make the quantity of the fuel gas to be supplied from the fuel tank12 the maximum, thereby lowering the excess air ratio and makingignition easy. When ignition is finished, the quantity of the fuel gasto be supplied from the fuel tank 12 is reduced by closing the cock 38 athereby increasing the excess air ratio. As a result, the flamespontaneously disappears and transition to catalytic combustion isquickly effected.

In the fifth example, as has been described above, a downsized and thincatalytic combustion apparatus is realized in which the valve 13 has aquantity-of-flow adjustable means 38, and ignition is made by operatingthe ignition device 14 while fully opening the quantity-of-flowadjustable means. Subsequently, by operating the quantity-of-flowadjustable means to control the quantity of supply of the fuel gas,stable transition to catalytic combustion is effected without fail.

EXAMPLE—6

A description of a sixth example of the present invention will now begiven. FIG. 14 is a cross-sectional view to illustrate the overallstructure of a catalytic combustion apparatus of this example. In thisexample, a temperature detecting means 40 is provided in a combustionchamber 21. A thermistor is used as the temperature detecting means 40in this example. Detected temperature information from the temperaturedetecting means 40 is transmitted to a control apparatus 39. The controlapparatus 39 has a relay circuit 37 and a temperature detecting circuit41.

Upon detecting that the temperature of a catalyst for combustion 22 hasreached a catalytic combustion enabling temperature based on thedetected temperature information from the temperature detecting means40, the control apparatus 39 controls a solenoid valve 34 so it istemporarily closed. As a result, the fuel gas supplied from a fuel tank12 is suspended at the time the temperature of the catalyst forcombustion 22 has reached the catalytic combustion enabling temperature.Accordingly, the flame burning in a firing chamber 19 is automaticallyextinguished thereby assuring transition to catalytic combustion.

As has been described above, according to the sixth example, byconstituting a valve 13 from the solenoid valve 34 and the controlapparatus 39, and controlling the control apparatus 39 so that thesolenoid valve 34 is temporarily closed by a signal from the temperaturedetecting means disposed in the combustion chamber 21, a downsized andthin catalytic combustion apparatus is realized in which ignition andtransition to catalytic combustion are performed with stability andcertainty.

EXAMPLE—7

Next, a description of a seventh example of the present invention willbe given. FIG. 15 is a cross-sectional view of a combustor of acatalytic combustion apparatus of this example. In this example, anexhaust port 23 is provided on the combustor 11 at a position notoverlapping a combustion chamber 21 and displaced in a directionopposite the direction of ejection of a mixed gas to a mixing chamber19.

As a result, the exhaust gas produced by catalytic combustion and to beexhausted from the exhaust port 23 will reach the exhaust port 23 whilemaking contact with the combustion chamber 21. In other words, as theamount of heat of the exhaust gas is absorbed by the combustion chamber21, or is used to increase the temperature of the combustion chamber 21,the temperature of the exhaust gas is reduced. Furthermore, in theconfiguration of the present example, that portion of the mixed gaswhich is powerful is made far from the exhaust port 23 and that portionof the mixed gas which is weak is made near to the exhaust port 23thereby allowing the mixed gas to uniformly pass through a catalyst forcombustion 22.

As has been described above, in the configuration of the seventhexample, by disposing the exhaust port 23 in the combustion chamber 21at a position not overlapping the combustion chamber 21 and opposite tothe direction of the mixed gas ejected into the mixing chamber 19, adownsized and thin catalytic combustion apparatus is obtained in which amixed gas uniformly passes through a catalyst for combustion therebyassuring uniform catalytic combustion.

EXAMPLE—8

Next, a description of an eighth example of the present invention willbe given. FIG. 16 is a cross-sectional view to illustrate the structureof a combustor of this example. In this example, a combustor 11 has aburner port area adjustable means 42 for adjusting the area of a burnerport 25. Also, the burner port area adjustable means 42 is operable witha signal from a temperature detecting means 43 provided in the vicinityof the burner port 25. The burner port area adjustable means 42comprises an L-shaped adjustable plate 42 and a tension spring 42 b. Onthe adjustable plate 42 are provided the same number and size ofadjustable holes 42 c as that of the burner port 25. Also, thetemperature detecting means 43 comprises a case 43 a, a bimetal 43 b andan operating rod 43 c. A heat sensing rod 43 d is secured to the case 43a for better exposure to the heat of a flame formed on the burner port25. The adjustable plate 42 a is positioned in such a way that thepositions of the adjustable hole 42 c and the burner port 25 agree whenthere is no flame.

Next, operation of this example will be described. When a flame isformed on the burner port 25, temperature of a catalyst for combustion22 rises to a catalytic combustion enabling temperature. At the sametime, the temperature of the heat sensing rod 43 d constituting thetemperature detecting means 43 rises by the flame and conducts theamount of heat to the bimetal 43 b. When the bimetal 43 b flips over onreceiving the amount of heat as shown in FIG. 17, the operating rod 43 calso moves. As the operating rod 43 c moves, the adjustable plate 42 awhich is in contact with the operating rod 43 c also moves. When theadjustable plate 42 a moves, the position of the adjustable holes 42 calso moves thereby displacing the positions of the adjustable holes 42 cand the burner port 25. In other words, the area of the aperture of theburner port 25 is reduced. When the area of the aperture of the burnerport 25 is reduced, the flame formed on the burner port 25 disappears.Consequently, the catalyst for combustion 22 can easily shift tocatalytic combustion. Also, when the flame disappears, the temperatureof the heat sensitive rod 43 d decreases, the bimetal 43 d flips backagain, and the adjustable plate 42 a returns to its original position bythe restoring force of the tension spring 42 b.

As has been described above, in this example, the catalyst forcombustion 22 can instantaneously start catalytic combustion.

EXAMPLE—9

Next, a description will be given of a ninth example of the presentinvention. FIG. 18 is a cross-sectional view to illustrate the structureof a combustor of this example. In this example, a catalyst forcombustion 22 is affixed in a combustion chamber 21 with a space 32between itself and the inner wall of the combustion chamber 21. To bemore specific, it is affixed between a pair of square C-shaped spacers31 provided on the inner wall 21 a of the combustion chamber 21.

By employing the above configuration, the amount of heat generated bythe catalyst for combustion 22 is kept inside the combustion chamber 21.That is, as the heat is retained by the layer of air existing in thespace 32, the heat of catalytic combustion is made difficult to beconducted to the inner wall 21 a. As a result, the temperature of theouter wall of the combustion chamber 21 is controlled to a low leveleven when the apparatus is downsized thereby providing an easy-to-usecatalytic combustion apparatus.

EXAMPLE—10

Next, a description of a tenth example of the present invention will begiven. FIG. 19 and FIG. 20 are cross-sectional views to illustrate theconfigurations of a combustion chamber of this example. In this example,a catalyst for combustion 22 is provided with a thickness adjustablemeans 33. The thickness adjustable means 33 is composed of apillar-shaped adjustable rod 33 a having an oval cross-section. In thisexample, the catalyst for combustion 22 comprises two catalysts, namely,a first catalyst 22 b and a second catalyst 22 c disposed in a mannersuch that the adjustable rod 33 a is sandwiched between them. When themajor axis of the adjustable rod 33 a is in the horizontal direction,the thickness of the catalyst for combustion 22 becomes thin asillustrated in FIG. 19, whereas, when in the vertical direction, thethickness becomes thick as illustrated in FIG. 20. In this way, thethickness of the catalyst for combustion 22 can be freely varied byrotating the adjustable rod 33 a.

Consequently, according to the tenth example, the quantity of heatgenerated by the catalyst for combustion 22 and conducted to a combustor11 can be adjusted by adjusting the space 32 between the inner wall 21 aof a combustion chamber 21 and the catalyst for combustion 22 therebyproviding a catalytic combustion apparatus with a wide temperaturecontrol range.

EXAMPLE—11

A description of an eleventh example of the present invention will begiven in the following. FIG. 21 is a cross-sectional view to illustratea catalytic combustion apparatus of this example. Numeral 51 is a gastank for storing liquefied petroleum gas such as butane and propane. Afuel gas inside the gas tank 51 is ejected from a gas nozzle 53 via agas passage 52. A valve (not shown) for adjusting quantity of gas flowis provided between the gas tank 51 and the gas nozzle 53. The fuel gasejected from the gas nozzle 53 draws in air from an air intake 54 by theejection effect of the gas flow and is mixed with air in a mixingchamber 55. The exit of the mixing chamber 55 communicates with astraight cylindrical gas passage 56. A side of the straight cylindricalgas passage 56 communicates with a combustion chamber 58 which has acatalytic body 57. In this example, the combustion chamber 58 isdisposed inside the straight cylindrical gas passage 56. In other words,an end portion of the combustion chamber 58 is positioned at a distanceD inward from an end portion of a straight cylindrical gas passage 56.

The catalytic body 57 is of a configuration as illustrated in FIG. 22.FIG. 22 is a perspective view to illustrate the shape of a catalyticbody used in this exemplary example. To be more specific, a continuouslycorrugated thin sheet of metal consisting of stainless steel or the likeis used as the carrier of the catalyst. In this example, a platinumgroup metal or an oxide of metals such as nickel, cobalt, iron,manganese, or chromium is used as the catalyst. Especially preferable isa platinum group metal such as platinum, palladium, or rhodium. Asillustrated in FIG. 22, the catalytic body 57 is formed in the shape ofa flat plate in a manner such that the planar area as represented bywidth A×length B is greater than the side area as represented by widthT×thickness B. In the eleventh example, this catalyst carrier can beeasily formed by processing a 0.05 to 0.1 mm thick stainless steel foil,for example. In other words, the catalyst carrier is one which is easyto continuously process and is superior in mass producibility.Furthermore, as the catalyst carrier is of a continuous corrugatedconfiguration, a large surface area per unit volume is obtainable. Thatis, improvement in catalytic performance can be expected.

FIG. 23 is a cross-sectional view of a section housing the abovedescribed catalytic body 57. When the catalytic body 57 is housed in thecombustion chamber 58, the corrugated portion “a” functions as a gaspassage. In other words, the combustion gas flows sideways passing thisgas passage (hereafter called gas passage “a”). Also, the combustion gasundergoes catalytic combustion while it passes the gas passage “a”.

Also, as illustrated in FIG. 21, an ignition device 59 is provided onthe side opposite to the entrance of the combustion chamber 58. Whenstarting, the ignition device 59 is operated to generate a spark on aplug 60 on the tip. A flame is formed downstream of the catalytic body57 by the spark, and the catalytic body 57 is heated by the flame. Whenthe temperature of the catalytic body 57 rises to the active temperatureof the catalyst, catalytic combustion begins on the surface of thecatalytic body 57 and the flame disappears. The mixed gas supplied tothe combustion chamber 58 undergoes catalytic reaction over the entiresurface of the catalytic body 57 and generates heat as it passes the gaspassage “a” of the catalytic body 57, and the combustion gas afterreaction is exhausted from an exhaust port 61.

In general, the amount of combustion of a catalytic combustion apparatusis determined by the area (cross-sectional area) of the entrance of thecatalytic body for the mixed gas if the catalytic material and thesurface area of the entire catalytic body are the same. Consequently,when only the thickness of the catalytic body is reduced, the area ofentrance is also reduced thus making it unable to obtain equivalentcombustion characteristics and resulting in a poor combustion rate. Forthis reason, in this example, entrance area is secured by increasing thewidth A to compensate for the reduction in the thickness T of thecatalytic body 57. As a result, according to the present example, thethickness can be reduced without reducing the combustioncharacteristics. Furthermore, as the catalytic body 57 is configured bycontinuous processing of a thin metal sheet as described before therebyto provide a large surface area per unit volume, further downsizing isenabled when compared with the prior art.

Next, a description will be given of the system of supplying a mixed gasto the catalytic body 57 as adopted in this example. The ejectionvelocity of the fuel gas ejected from the nozzle 53 is on the order ofseveral 100 m/sec and the velocity of flow of the mixed gas flowing outfrom the mixing chamber 55 is also very high. In order to uniformlysupply the mixed gas to the low-profile catalytic body 57, it isnecessary to reduce the flow velocity of the mixed gas and to make thedistribution of flow velocity uniform over the entire entrance of thecombustion chamber 58. In general practice, a diffuser is provided atthe exit of the mixing chamber 55 to gradually widen the area of thepassage thereby making the flow velocity uniform. However, in thismethod, a longer diffuser is needed as the width of the entrance of thecombustion chamber 58 increases, thereby resulting in a catalyticcombustion apparatus having longer length and larger width.

On the contrary, in this example, a communicating straight cylindricalgas passage 56 is provided at the exit of the mixing chamber 55 as hasbeen described, and an entrance to the combustion chamber 58 is formedon a side of the straight cylindrical gas passage 56 so as tocommunicate with the entrance. In other words, the positionalrelationship between the mixing chamber 55 and the catalytic body 57 isnot serial but parallel. As a result, according to this example, theoverall length of the combustion apparatus can be shortened and theapparatus can be compactly configured.

The mixed gas from the mixing chamber 55 first linearly flows inside thestraight cylindrical gas passage 56. When the mixed gas impinges thefront end portion 56 a of the straight cylindrical gas passage 56, areverse flow is caused inside the straight cylindrical gas passage 56due to impingement. This reverse flow and the mixed gas supplied by themixing chamber 55 interfere with each other. As a result, the flowvelocity inside the straight cylindrical gas passage 56 becomesdrastically small, static pressure of the entire inside of the straightcylindrical gas passage 56 increases, and the mixed gas flows to thedirection of the combustion chamber 58 that communicates with the sideof 50 the straight cylindrical gas passage 56. In this example, asillustrated in FIG. 21, the length of the straight cylindrical gaspassage 56 is designed to be longer than the width of the entrance ofthe combustion chamber 58 and the entrance portion of the combustionchamber 58 is disposed within the length of the straight cylindrical gaspassage 56. To be more specific, the position of the end portion of thecombustion chamber 58 is recessed by a distance D from the end portion56 a of the straight cylindrical gas passage 56. Consequently, thereverse flow gas arising from the impingement at the front end portion56 a of the straight cylindrical passage 56 is prevented from directlyentering into the combustion chamber 58, and the mixed gas uniformlymixed with air can be uniformly supplied into the combustion chamber 58.In other words, as the mixed gas is supplied to the combustion chamber58 at this stage, the flow velocity has reduced due to the abovedescribed interference, the overall static pressure has risen, and themixed gas to be supplied to the combustion chamber 58 will become one inwhich the fuel gas and air are more uniformly mixed during the time thestatic pressure rises. Also, the distribution of flow velocity of themixed gas at the entrance of the combustion chamber 58 will becomeuniform thereby enabling uniform supply of the mixed gas to thecatalytic body 57.

According to experiments by the present inventors, the catalyticcombustion apparatus of the present example provides combustion heat of60 watts or higher when the size is 6 mm in thickness and 50 mm inlength. Consequently, when it is used in a warming cloth to be worn forwarming the body, for example, there will be no feeling of discomfortand a product with superior portability may be realized.

Also, an apparatus with combustion heat on the order of 10 watts can berightfully configured smaller and thinner than the above-mentioneddimension thus enabling use in small warmers such as gloves, shoes, orsocks, for warming fingers or toes, or in thermotherapy curing devicesfor treatment by applying the hot spot to arbitrary effective points.

Furthermore, in this example, a gas resistant body 62 made of metal meshor expanded metal or the like is provided at the exit of the mixingchamber 55 as illustrated in FIG. 21. The gas resistant body 62 reducesthe flow velocity of the mixed gas coming out from the mixing chamber 55thereby reducing the flow velocity inside the straight cylindrical gaspassage 56. As a result, the distribution of flow velocity of the mixedgas at the entrance of the combustion chamber 58 can be made furtheruniform. In other words, by the use of the gas resistant body 62, thediameter of the straight cylindrical gas passage 56 can be made smallerthereby enabling reduction of the overall size of the combustionapparatus.

In addition, in this example, a gas rectifier 63 made of metal mesh orexpanded metal or the like is provided at the entrance of the combustionchamber 58. The gas rectifier 63 acts in a manner such that a mixed gasflowing from the straight cylindrical gas passage 56 to the combustionchamber 58 is rectified. Even when a vortex of mixed gas flow isproduced inside the straight cylindrical gas passage 56 due to reasonssuch as fluctuation in the quantity of flow of the fuel gas, stablesupply of mixed gas to the entire catalytic body 57 is enabled.

EXAMPLE—12

Next, a description will be given on a twelfth example of the presentinvention. FIG. 24(a) is an exploded perspective view of a catalyticbody 64 employed in a catalytic combustion apparatus of the presentexample. FIG. 24(b) is an assembled perspective view of the catalyticbody 64. The catalytic body 64 is comprised of corrugated sheets 65 and65′ made by continuously folding thin metal sheets of stainless steel orthe like and a flat plate 66 of a thin metal sheet. In this example, thecorrugated sheets 65 and 65′ are made of 0.05 mm thick thin metal sheetsand the flat plate 66 is made of a 0.1 mm thick thin metal sheet. Acatalyst carrier is configured by stacking by spot welding, for example,one or more of these into a multilayer structure. The catalyst supportedby this catalyst carrier is the same as described in the first example.Similar to the description in the first example, the catalytic body 64is of a flat plate configuration in which the planar area is greaterthan the cross-sectional area. Also, when housed in a combustion chamber58, the waved portion forms a gas passage along which a mixed gas flowsin the lateral direction.

According to the twelfth example, by configuring the catalytic body 64with a multilayer body of metal as has been described above, the surfacearea per unit volume can be made greater than the configurationdescribed in the first example. As a result, when the size of thecatalytic body is the same, larger amounts of combustion can beobtained.

Also, when the catalytic combustion apparatus is in operation, the flatplate 66 will not come into contact with the inner wall of thecombustion chamber 58. Consequently, when adjusting the temperature ofthe flat plate 66 which has risen higher than the temperature of thecorrugated sheets 65 and 65′ by turning on and off the fuel gas, it iseasy to maintain an active temperature of the catalyst. That is,elimination of combustion is made difficult.

Also, the temperature difference between upstream and downstreamportions of the mixed gas undergoing catalytic combustion on thecatalytic body 64 is made smaller by the heat unifying action of theflat plate 66. Accordingly, the present example is also advantageous tothe life of the catalytic body 64.

Even though the corrugated sheets 65 and 65′ were configured from 0.05mm thick thin metal sheets and the flat plate 66 from a 0.1 mm thickthin metal sheet, the thickness is not restricted to these values.

EXAMPLE—13

Next, a description will be given of a thirteenth example of the presentinvention. FIG. 25 is a perspective view to illustrate the configurationof a catalytic body 67 employed in a catalytic combustion apparatus ofthe present invention. In this example, the catalytic combustionapparatus comprises a corrugated sheet 68 made by folding a thin metalsheet in the form of continuous waves, a corrugated sheet 70 madesimilarly, a corrugated sheet 72 made similarly, a flat plate 69 made ofa thin metal sheet, and a flat plate 71 made similarly. A multilayermetal catalyst is made by joining these sheets and plates by spotwelding, for example.

With the configuration of the present example, an amount of combustionapproximately 1.5 times that of the configuration described in thetwelfth example is obtained. As has been described above, according tothe present example, the entrance area for a mixed gas and the surfacearea of the catalyst can be enlarged by increasing the number of stackedlayers, and catalytic bodies with different amounts of combustion can befabricated by increasing or decreasing only the number of components forconfiguring the catalytic body. Consequently, standardization ofcomponents is made easy thus enabling low cost manufacturing.

EXAMPLE—14

A description of a fourteenth example of the present invention will begiven in the following. FIG. 26 is a cross-sectional view to illustratethe configuration of a catalytic combustion apparatus of the presentexample. Numeral 81 is a gas tank for storing liquefied petroleum gassuch as butane or propane. The fuel gas inside the gas tank 81 isejected from ejection outlet 83 a of a nozzle 83 via a gas passage 82. Acontrol valve 84 for adjusting gas flow rate is provided between the gastank 81 and the nozzle 83. The fuel gas ejected from the ejection outlet83 a draws in air through an air intake 85 and is mixed with air in amixing chamber 86. The exit of the mixing chamber 86 communicates with aroughly cylindrical gas passage 87. A side of the cylindrical gaspassage 87 communicates with a combustion chamber 90 having a catalyticbody 89 via a firing chamber 88 which is disposed adjacent to the sideof the gas passage 87.

The catalytic body 89 has a honeycomb cross-section as illustrated by aside view of FIG. 27, for example, and supports as a catalyst a platinumgroup metal or oxide of such metals as nickel, iron, manganese, orchromium on a carrier formed by corrugating thin metal sheets ofstainless steel or the like. The fuel gas mixed with air undergoescatalytic combustion by catalytic action while it passes inside thecatalytic body 89 after passing through the gas passage 87 and thefiring chamber 88.

Also, an ignition device 91 is provided on the upper part of the firingchamber 88. When starting the apparatus, a spark (high voltage electricdischarge spark) is generated by a plug 91 a on the tip by operating theignition device 91. With this spark, a flame is formed inside the firingchamber 88, and the catalytic body 89 is heated by the flame. Numeral 92is a high tension wire to supply electricity to the ignition device 91.When the temperature of the catalytic body 89 rises and reaches anactive temperature of the catalyst, heat is generated on the surface ofthe catalytic body 89 due to catalytic reaction, and the combustion gasafter reaction is exhausted from an exhaust port 93. Numeral 94 is atemperature detecting means for detecting the temperature of thecombustion chamber 90 and comprises a thermistor, thermocouple or thelike, and is connected to a control unit 95. The control unit 95 isdesigned in a manner such that it controls the quantity of ejection ofthe fuel gas by driving a control valve 84 depending on the output fromthe temperature detecting means 94 and adjusts the temperature of thecombustion chamber 90.

The components used in the above system of the fourteenth example willnow be described. As illustrated in FIG. 26, FIG. 27, and FIG. 28, thecombustion chamber 90, the firing chamber 88, and the gas passage 87,comprise two components divided by a plane parallel to the direction offlow of the mixed gas, namely, a lower base 96 and an upper base 97.Numeral 98 is a nozzle unit that integrates the air intake 85, themixing chamber 86, and the nozzle 83 and is made by inserting the nozzle83 into a cast component. It is also possible to configure the nozzleunit as an integral unit entirely by performing cutting operations. Inthis example, as illustrated in FIGS. 27 and 28, the nozzle unit 98,catalytic body 89, ignition device 91, and temperature detecting means94 are sandwiched between the two components, namely, the lower base 96and the upper base 97, at a predetermined position, and secured byscrewing fixing screws 99 into screw holes 100 provided on the lowerbase 96.

By making the nozzle 83 and the mixing chamber 86, that require a highdegree of precision of processing, as separate and divisible componentsfrom the combustion chamber 90, and the firing chamber 88, the shape ofthe lower base 96 and the upper base 97 can be simplified thereby makingprocessing easy, allowing reduction of the material thickness to aminimum thus enabling downsizing and a thinner design. Also, the nozzleunit 98 itself which requires a high degree of precision processing ismade easier to process, suggesting the possibility of further downsizingby configuring an integral unit by preforming cutting operations asdescribed before.

Also, as the combustion chamber 90 is divided into the lower base 96 andthe upper base 97 by a plane roughly in parallel to the direction ofejection of the nozzle, the configuration for processing of thecombustion chamber 90 section is greatly simplified thereby makingprocessing easy, allowing reduction of the material thickness to aminimum thus achieving a low profile.

Furthermore, as the combustion chamber 90 section is divided into upperand lower units, housing of the catalytic body 89 during assembly ismade easy. Also, the assembling of the nozzle unit 98, the ignitiondevice 91, and the temperature detecting means 94 is likewise easilydone, especially, as the temperature detecting means 94 has to detectthe temperature of the combustion chamber 90 through heat conduction.Although it is a general practice to fix the temperature detecting means94 by pressing with a separate component made of a good heat conductorto ensure temperature detection, structure for fixing can be simplifiedby securing it with the lower base 96 and the upper base 97 whilesandwiching it as in this configuration, and temperature detection withhigher reliability is assured.

INDUSTRIAL APPLICATION

A catalytic combustion apparatus of the present invention comprises acombustor, a fuel tank, a valve, and an ignition device, and thecombustor further comprises a gas nozzle, an air intake/ejector, amixing chamber, a firing chamber, an ignition plug, a combustionchamber, a catalyst for combustion housed in the combustion chamber, andan exhaust port. The mixing chamber is made into a straight cylindricalpassage, a cylindrical firing chamber is provided in parallel to themixing chamber via an opening on the side of the firing chambercommunicating with the combustion chamber, a burner port is disposed onthe boundary between the mixing chamber and the firing chamber, and theburner port comprises a catalyst net. With this configuration, thecatalyst for combustion can start catalytic combustion by forming aflame on the upstream side of the catalyst for combustion and heatingthe catalyst for combustion to a catalytic combustion enablingtemperature with the heat of the flame thereby also causing catalyticcombustion on the catalytic net, whereupon the flame spontaneously isextinguished allowing the combustion catalyst to commence catalyticcombustion and suggesting that catalytic combustion can be effectedwithout fail even when the combustion chamber is configured with a lowprofile. Furthermore, as the combustion takes place on both thecatalytic net and the catalyst for combustion, the temperature rise ofthe catalyst for combustion is kept small and its life is lengthened. Asa result, the thickness of the catalytic body can be made smallerwithout sacrificing the igniting characteristics and durability, therebyenabling reduction in the burner height and providing a smaller andthinner catalytic combustion apparatus.

What is claimed is:
 1. A catalytic combustion apparatus comprising: apassage for creating a mixture of air and fuel gas; a combustionchamber, in fluid communication with said passage along a firstdirection that is generally transverse to a direction along which theair and fuel gas are to be introduced into said passage, for receivingthe mixture of air and fuel gas from said passage along said firstdirection; a catalyst for combustion within said combustion chamber; afiring chamber in fluid communication with said passage along said firstdirection and in fluid communication with said combustion chamber alongsaid first direction, wherein said combustion chamber is in fluidcommunication with said passage along said first direction via saidfiring chamber; and a burner port between said passage and said firingchamber, said burner port comprising a plate having through holes,wherein said passage is in fluid communication with said firing chamberalong said first direction via said through holes.
 2. The catalyticcombustion apparatus according to claim 1, wherein said plate comprisesa net supporting a catalyst.
 3. The catalytic combustion apparatusaccording to claim 2, wherein said passage is at least partially definedby a wall, and part of said net is in contact with said wall.
 4. Thecatalytic combustion apparatus according to claim 1, wherein saidpassage includes an inlet through which air and fuel gas are to beintroduced into said passage, and said firing chamber is at leastpartially defined by a wall, and further comprising: an ignition deviceon said wall at a position that is opposite to said inlet.
 5. Thecatalytic combustion apparatus according to claim 1, further comprising:a combustor that includes said passage, said firing chamber and saidcombustion chamber; a fuel tank, in fluid communication with saidcombustor, for supplying fuel gas to said combustor; an ignition device,in operative association with said combustor, for igniting the fuel gaswithin said combustor; and a solenoid valve, positioned between saidfuel tank and said combustor, for controlling the supply of fuel gasfrom said fuel tank to said combustor, wherein said solenoid valve is tobe closed within a predetermined time period after said ignition devicehas ignited the fuel gas within said combustor such that supply ofadditional fuel gas from said fuel tank to said combustor is prevented,and subsequently said solenoid valve is to be re-opened to allowadditional supply of fuel gas from said fuel tank to said combustor. 6.The catalytic combustion apparatus according to claim 1, furthercomprising: a combustor that includes said passage, said firing chamberand said combustion chamber, and further includes an air intake; anignition device, in operative association with said combustor, forigniting fuel gas within said combustor; and an air-intake shutter,positioned at said air intake of said combustor, for controlling thesupply of air into said combustor, wherein said air-intake shutter is tobe operated within a predetermined time period after said ignitiondevice has ignited the fuel gas within said combustor such that supplyof air into said combustor is controlled.
 7. The catalytic combustionapparatus according to claim 1, further comprising: a combustor thatincludes said passage, said firing chamber and said combustion chamber;an ignition device, in operative association with said combustor, forigniting fuel gas within said combustor; and structure, in operativeassociation with said burner port, for adjusting an effective area ofsaid through holes such that the supply of the mixture of air and fuelgas into said firing chamber from said passage is controllable, whereinsaid structure is to be operated within a predetermined time periodafter said ignition device has ignited the fuel gas within saidcombustor such that the supply of the mixture of air and fuel gas intosaid firing chamber from said passage is controlled.
 8. The catalyticcombustion apparatus according to claim 7, wherein said structure foradjusting the effective area of said through holes comprises a movableplate that has through holes corresponding to said through holes of saidplate of said burner port, such that the supply of the mixture of airand fuel gas to said firing chamber from said passage is controllable bymoving said movable plate relative to said plate of said burner port,whereby said through holes of said movable plate become aligned withsaid through holes of said plate of said burner port or becomemis-aligned with said through holes of said plate of said burner port.9. The catalytic combustion apparatus according to claim 1, furthercomprising: a combustor that includes said passage, said firing chamberand said combustion chamber, and further includes a temperature sensor;a fuel tank, in fluid communication with said combustor, for supplyingfuel gas to said combustor; and a solenoid valve, positioned betweensaid fuel tank and said combustor, for controlling the supply of fuelgas from said fuel tank to said combustor, wherein said solenoid valveis to be temporarily closed in response to a temperature sensed by saidtemperature sensor.
 10. The catalytic combustion apparatus according toclaim 1, further comprising: a combustor that includes said passage,said firing chamber and said combustion chamber, and further includes anair intake and a temperature sensor; and an air-intake shutter,positioned at said air intake of said combustor, for controlling thesupply of air into said combustor, wherein said air-intake shutter is tobe operated in response to a temperature sensed by said temperaturesensor.
 11. The catalytic combustion apparatus according to claim 1,further comprising: a combustor that includes said passage, said firingchamber and said combustion chamber, and further includes a temperaturesensor; and structure, in operative association with said burner port,for adjusting an effective area of said through holes such that thesupply of the mixture of air and fuel gas into said firing chamber fromsaid passage is controllable, wherein said structure is to be operatedin response to a temperature sensed by said temperature sensor.
 12. Thecatalytic combustion apparatus according to claim 11, wherein saidstructure for adjusting the effective area of said through holescomprises a movable plate that has through holes corresponding to saidthrough holes of said plate of said burner port, such that the supply ofthe mixture of air and fuel gas to said firing chamber from said passageis controllable by moving said movable plate relative to said plate ofsaid burner port, whereby said through holes of said movable platebecome aligned with said through holes of said plate of said burner portor become mis-aligned with said through holes of said plate of saidburner port.
 13. The catalytic combustion apparatus according to claim1, wherein a part of said catalyst for combustion projects into saidfiring chamber.
 14. The catalytic combustion apparatus according toclaim 1, wherein said catalyst for combustion includes a first surfacecontained within a plane, with said first surface having a length and awidth, said catalyst combustion apparatus also includes a second surfacecontained within a plane, with said second surface having a width thatextends transverse to the width of said first surface and is less thanthe width of said first surface, and with said second surface having alength that extends parallel to the length of said first surface and isequal to the length of said first surface, and said catalytic combustionapparatus also includes passages extending along the width of said firstsurface to allow for the flow of gas through said passages.
 15. Thecatalytic combustion apparatus according to claim 1, wherein saidcatalyst for combustion comprises a catalyst supported by a catalystsupport that comprises a thin metal corrugated carrier that definesalternating peaks and valleys, with said peaks being contained within aplane and bound by an area defined by a width of said peaks and a firstlength from a first of said peaks to a last of said peaks, said thinmetal corrugated carrier also defines a side surface having a width thatis less than and extends transverse to the width of said peaks and alsohaving a length that extends parallel to and is equal to said firstlength, and with the area between said peaks and valleys definingpassages extending along the width of said peaks to allow for the flowof gas through said passages.
 16. The catalytic combustion apparatusaccording to claim 15, wherein said catalyst support further includes aflat plate on said peaks and another said thin metal corrugated carrieron said flat plate.
 17. A catalytic combustion apparatus comprising: apassage for creating a mixture of air and fuel gas; a combustionchamber, in fluid communication with said passage along a firstdirection that is generally transverse to a direction along which theair and fuel gas are to be introduced into said passage, for receivingthe mixture of air and fuel gas from said passage along said firstdirection; a catalyst for combustion within said combustion chamber; anda firing chamber in fluid communication with said passage along saidfirst direction and in fluid communication with said combustion chamberalong said first direction, wherein said combustion chamber is in fluidcommunication with said passage along said first direction via saidfiring chamber, wherein said passage, said firing chamber and saidcombustion chamber are defined between plural components that areseparated from one another by a plane that extends generally parallel tothe direction in which the air and fuel gas are to be introduced intosaid passage and generally transverse to said first direction.
 18. Thecatalytic combustion apparatus according to claim 17, wherein saidplural components define said combustion chamber, and a component bodyintegrating a mixing chamber and a nozzle is sandwiched between andsecured to said plural components such that said passage is in fluidcommunication with said nozzle via said mixing chamber.